Room-temperature driven and visible light enhanced dehydrogenation reactions catalysed by basic Au/SrTiO3

An Au/SrTiO3 catalyst with basic properties (Au/SrTiO3-urea) was reported for the first time to be efficient for the dehydrogenation of secondary alcohols at room temperature, with iso-propanol (IPA) dehydrogenation as the probe reaction. Different from previous reports that Au/SrTiO3 was generally regarded as only a photocatalyst in the IPA dehydrogenation reaction, in this work, it was found that Au/SrTiO3-urea could also catalyse the reaction at room temperature without light irradiation, with an acetone production rate of 8.2 μmol h-1 (IPA conversion of 41.0%) which was more than 10 times higher than that of Pt/TiO2 evaluated under the same conditions. Characterization results revealed that the lattice oxygen in SrTiO3 was involved in the reaction through the Mars-van Krevelen mechanism, while Au facilitated the cleavage of C-H bonds of the adsorbed reactant with the assistance of a base. Its catalytic activity was further increased to 16.5 μmol h-1 (IPA conversion of 82.5%) after the introduction of visible light. It is regarded that the photon induced photocatalytic performance was significantly enhanced with the existence of instantaneously generated oxygen vacancies. Additionally, the conversion of IPA (82.5%) and the rate of acetone production over Au/SrTiO3-urea (16.5 μmol h-1) after visible light irradiation for 1 h were 12.3 times and 2.5 times as high as those over Au/P25 (IPA conversion of 6.7% and acetone production rate of 6.7 μmol h-1), a catalyst which was also reported to be active in IPA dehydrogenation without light irradiation. This study provides a method for designing efficient catalysts for the dehydrogenation of secondary alcohols at room temperature.